All-Optical Tunable Whispering Gallery Modes in a Polymer Bottle Micro-Resonator

We propose and demonstrate an all-optical tunable polymer bottle micro-resonator fabricated by droplet dispensing method. A microfiber is used to excite whispering gallery mode (WGM) of the micro-resonator. Continuous wave (CW) laser is employed as pump light to tune the WGM. To illustrate tuning performance of the fabricated device, external and internal pump light methods are both employed. For external pump light method, the tuning efficiency is about 5.23 pm/mW. For internal pump light, tuning efficiency of 68.3 pm/mW is obtained. The experimental results reveal that the bottle micro-resonator (BMR) can achieve wavelength tuning more than one free spectral range (FSR), which indicates the WGM can be tuned within a transparent window covered the full wavelength range. In addition, the fabricated device has advantages of high tuning efficiency, small size, easy fabrication, and extremely low cost.